Aerosol vaccination against Newcastle disease: virus inhalation and retention during vaccination

During aerosol vaccination of chickens with the LaSota strain of Newcastle disease virus, the quantities of inhaled and expired virus were determined by sampling the inhaled and expired air with a "capillary impinger", and virus retention in the respiratory tract was calculated. In serial experiments under smi-field conditions virus was nebulised in an amount of 4.4 +/- 0.4 log(10) EID50 per litre of air. The concentration of virus in the aerosol during 30 min following nebulisation was 2.8 +/- 0.4 logio EID50/1. The concentration of virus in the sampled air inhaled by the chickens as calculated per litre, was an average 2.4 +/- 0.49 log(10) EID50/1 and in the expired air 1 to 100 EID50/1. Comparison of the results shows that virus retention is such as to permit lodgement of a sufficient number of particles to produce what has been shown elsewhere to be an effective immunisation.